2/23/2009 @ 1:47PM

The Dangers Of Overselling Evolution

Last week, University of Chicago biologist Jerry Coyne criticized Forbes (See “Why Evolution Is True”) for including views skeptical of Charles Darwin’s theory of evolution in its forum on the 200th anniversary of his birth. As a member of the National Academy of Sciences, I beg to differ with Professor Coyne.

I don’t think science has anything to fear from a free exchange of ideas between thoughtful proponents of different views. Moreover, there are a number of us in the scientific community who, while we appreciate Darwin’s contributions, think that the rhetorical approach of scientists such as Coyne unnecessarily polarizes public discussions and­–even more seriously­–overstates both the evidence for Darwin’s theory of historical biology and the benefits of Darwin’s theory to the actual practice of experimental science.

Coyne seems to believe the major importance of biological science is its speculations about matters which cannot be observed, tested and verified, such as origin of life, speciation, the essences of our fossilized ancestors, the ultimate causes of their changes, etc.

Experimental biology has dramatically increased our understanding of the intricate workings within living organisms that account for their survival, showing how they continue to function despite the myriad assaults on them from their environments. These advances in knowledge are attributable to the development of new methodologies and instruments, unimaginable in the preceding centuries, applied to the investigation of living organisms. Crucial to all fruitful experiments in biology is their design, for which Darwin’s and Wallace’s principles apparently provide no guidance.

Contrary to the beliefs of Professor Coyne and some other defenders of Darwin, these advances are not due to studies of an organism’s ancestors that are recovered from fossil deposits. Those rare artifacts–which have been preserved as fossils–are impressions in stones which, even when examined with the heroic efforts of paleontologists, cannot reveal the details that made these amazing living organisms function.

To conflate contemporary scientific studies of existing organisms with those of the paleontologists serves mainly to misguide the public and teachers of the young. An examination of the papers in the National Academy of Sciences’ premiere journal, The Proceedings of the National Academy of Sciences (PNAS), as well as many other journals and the Nobel awards for biological discoveries, supports the crucial distinction I am making.

Examining the major advances in biological knowledge, one fails to find any real connection between biological history and the experimental designs that have produced today’s cornucopia of knowledge of how the great variety of living organisms perform their functions. It is our knowledge of how these organisms actually operate, not speculations about how they may have arisen millions of years ago, that is essential to doctors, veterinarians, farmers and other practitioners of biological science.

It is widely accepted that the growth of science and technology in the West, which accounts for the remarkable advances we enjoy today in medicine, agriculture, travel, communications, etc., coincided with the separation, several centuries ago, of the experimental sciences from the dominance of the other important fields of philosophy, metaphysics, theology and history.

Yet many popularizers of Darwin’s theory now claim that without the study of ancient biological history, our students will not be prepared to engage in the great variety of modern experimental activities expected of them. The public should view with profound alarm this unnecessary and misguided reintroduction of speculative historical, philosophical and religious ideas into the realms of experimental science.

It is more crucial to consider history in the fields of astrophysics and geology than in biology. For example, the electromagnetic radiations arriving at our detectors inform us of the ongoing events that occurred billions of years ago in distant parts of our universe that have been traveling for all this time to reach us. And the rock formations of concern to geologists have resided largely undisturbed since their formations.

But fossils fail to inform us of the nature of our ancient antecedents–because they have been transformed into stones that give us only a minuscule, often misleading impression of their former essences and thus are largely irrelevant to modern biology’s experimentations with living organisms.

For instance, we cannot rely upon ruminations about the fossil record to lead us to a prediction of the evolution of the ambient flu virus so that we can prepare the vaccine today for next year’s more virulent strain. That would be like depending upon our knowledge of ancient Hittite economics to understand 21st-century economics.

In 1942, Nobel Laureate Ernst Chain wrote that his discovery of penicillin (with Howard Florey and Alexander Fleming) and the development of bacterial resistance to that antibiotic owed nothing to Darwin’s and Alfred Russel Wallace’s evolutionary theories.

The same can be said about a variety of other 20th-century findings: the discovery of the structure of the double helix; the characterization of the ribosome; the mapping of genomes; research on medications and drug reactions; improvements in food production and sanitation; new surgeries; and other developments.

Additionally, I have queried biologists working in areas where one might have thought the Darwinian paradigm could guide research, such as the emergence of resistance to antibiotics and pesticides. Here, as elsewhere, I learned that evolutionary theory provides no guidance when it comes to choosing the experimental designs. Rather, after the breakthrough discoveries, it is brought in as a narrative gloss.

The essence of the theory of evolution is the hypothesis that historical diversity is the consequence of natural selection acting on variations. Regardless of the verity it holds for explaining biohistory, it offers no help to the experimenter–who is concerned, for example, with the goal of finding or synthesizing a new antibiotic, or how it can disable a disease-producing organism, what dosages are required and which individuals will not tolerate it. Studying biohistory is, at best, an entertaining distraction from the goals of a working biologist.

It is noteworthy that Darwin’s and Wallace’s theories of evolution have been enormously aggrandized since the 1850s. Through the writings of neo-Darwinian biologists, they have subsumed many of the biological experimental discoveries of the 20th century. This is so despite the fact that those discoveries were neither predicted nor heuristically guided by evolutionary theory.

The overselling of the theory of evolution, because of the incorporation of these later discoveries, may have done a grave disservice both to those two 19th-century scientists and to modern biology.

The difference between the advances of 20th-century chemical and biological knowledge and the contentious atmosphere that currently prevails in biology alone is worth noting.

Chemists have depended largely on geological sources, from which they have isolated the hundred or so elements on the periodic table and subsequently devised a great variety of schemes for synthesizing millions of new complex arrangements of these elements, giving to the public medicines, fertilizers, plastics, etc., of great utility.

Biologists, on the other hand, have recognized that the natural sources they study are living organisms, each of which is a unique individual, each of which consists of extraordinary complex molecular combinations in configurations that lead to coherent functioning and reproduction. There are no two identical genomes in the biocosm. Now, modern biologists conduct experimental studies that have begun to reveal details of how living organisms function and reproduce.

It is unseemly and scientifically unfruitful that a major focus in biology should have turned into a war–between those who hold that the history of those unique organisms is purely a matter of chance aggregation from the inorganic world and those who hold that the aggregation must have been designed for a purpose.

It is surely not a matter that must or can be settled within the provenance of experimental biology. Above all, declaiming orthodoxy to either of those propositions promotes incivility and draws energy and resources away from the real goal–advances in experimental biological science. These studies, if not derailed, indicate that further advances of great utility can be expected during the 21st century.

Philip S. Skell is emeritus Evan Pugh professor of chemistry at Penn State University and a member of the National Academy of Sciences.